I've been user of Buffer for about a year now (June 2012). They were in the news yesterday so I figured I'd chime in on how much I love their service. It's an amazing app that I use on a daily basis. It provides a quick and easy way to do two things: cross-post to multiple social networks and queue social shares to be posted at a later date.
I don't often use it to queue posts but I find it the best way by far to cross-post to Twitter, Facebook, ADN or whatever network I'm sharing to. It has a great browser extension, integrates into many of apps I use such as Reeder and Pocket and also has a mobile app. It also automatically shortens all URLs using my custom brac.co Bitly Pro account which is pretty cool.